lightning

[Wayne Grenier]

We pretty much got struck by lighting Tuesday afternoon trying to get into Cutyhunk pond during the height of a nasty squall of the Mass/RI coast It was hitting everywhere around us but after I tied up I found the in line fuses for the vhf, am/fm and the radar where all blown. They are are located close to each other. Replacing the fuses did not work. I figure the vhf and the am/fm are not worth fixing, hopefully the radar can be repaired. The point is the boat itself 9and the people aboard) where all ok. It seems the cape dory "lighting rod" dynaplate grounding system works as it should. According to my son lighting hit the water about 15' from the boat. I couldn't see anything due to the hail and rain but I believe him. He's 13 and he and his friends thought it was coolest thing they'd ever seen and can't wait to go again? go figure. Anyway it might be a good argument for hand held/battery powered electronics-

[BillNH]

What probably toasted your electronics was not a direct hit, as your son observed, but the electromagnetic field caused by the lightning. As we may (or may not) remember from HS physics, a current induces a magnetic field around it, which then can induce a current in a nearby wire. The EMF of a lightning strike nearby blew all my electronics on a 37' trimaram that we used to live aboard a number of years ago. Not just the obvious casualties like VHF and GPS, but also the alternator charge controller and a handheld VHF... Yet absolutely no damage to the batteries or the vessel itself.

Handheld devices may be better than hard wired (grounded) ones as far as EMF effects of lightning, but they're not immune from damage.